A need for an improvement in trigger sprayers was clearly established years ago. Then as is the case now, the object was to develop such a sprayer which would cost no more to manufacture than the presently, widely used trigger sprayers. A further object was to develop a trigger pump which would at least have some of the following characteristics:
(a) a more forceful spray PA1 (b) greater output per stroke PA1 (c) instant priming PA1 (d) flexibility as to volume dispensed without major molding tool changes PA1 (e) ability to generate a foam, mist, spray and stream, if necessary. PA1 (1) A sliding engagement between the trigger and shaft of the piston which reduces turning moments that would cause binding of the piston in the cylinder. PA1 (2) A nozzle moveable with the piston. PA1 (3) A self sealing vent opening at an optimum location. PA1 (4) The ability to change and select trigger leverage. PA1 (5) The ability to utilize either an external spring for biasing the piston to its fully retracted position. PA1 (6) The ability to use the pump itself to seal the container which may then be a shipper without extra caps or seals.
Many trigger pumps have been proposed in patents, literature and to a lesser extent commercially. All are not complete in satisfying all commercial needs and applications. To this end, trigger pumps that are not restricted to product to be dispensed have been extremely costly. Those trigger pumps of reduced cost cannot dispense petroleum based product because of seal degradation. Other trigger pumps simply do not possess eye appeal or sufficient aesthetics to be commercially feasible.